The quote you posted states that the rate during the initial...

The quote you posted states that the rate during the initial term was 20%, that's what they are charging PNC.

'Under the Facility Agreement, the Company will owe a principal amount of $141.6 million to Carlyle, due on 20 September 2020. The interest rate under the facility is currently 20% per annum and there is a make whole payment which requires the Company to pay a minimum of 9 months of interest. Upon early refinance of the facility, Carlyle calculate the amount due as approximately $165.8m. '

You never assume an agreement is going to happen until it's signed, court approved & agreed by shareholders.
PNC would have been accruing interest in their monthly mngt accounts at 20%.
So until the agreement was approved by shareholders & the facility was extended the rate was 20%.

That's obviously where you've also gone wrong because you assumed Carlye would complete the transaction , otherwise you wouldn't be sitting on a hefty loss.